By John Irish
PARIS (Reuters) - An exiled Iranian opposition group said on Thursday that a delegation of North Korean nuclear and missile experts visited a military site near Tehran in April amid talks between world powers and Iran over its nuclear program.
The dissident National Council of Resistance of Iran (NCRI) exposed Iran's uranium enrichment plant at Natanz and a heavy water facility at Arak in 2002. Analysts say it has a mixed record and a clear political agenda.
Iran says allegations that is trying to develop a nuclear weapons capability are baseless and circulated by its enemies.
Iran and six world powers are trying to meet a self-imposed June 30 deadline to reach a comprehensive deal restricting its nuclear work. Issues remaining include monitoring measures to ensure it cannot pursue a clandestine nuclear weapons program.
Citing information from sources inside Iran, including within Iran's Revolutionary Guards Corps, the Paris-based NCRI said a seven-person North Korean Defense Ministry team was in Iran during the last week of April. This was the third time in 2015 that North Koreans had been to Iran and a nine-person delegation was due to return in June, it said.
"The delegates included nuclear experts, nuclear warhead experts and experts in various elements of ballistic missiles including guidance systems," the NCRI said.
The Iranian embassy in France dismissed the report.
"Such fabricated reports are being published as we get closer to final stages of the talks and also because there is a high chance of reaching a final deal," Iran's state website IRIB quoted an unnamed Paris-based Iranian diplomat as saying.
In Washington, the State Department said it was examining the claims but had been unable to confirm them.
"These allegations, we're taking them seriously," State Department spokesman Jeff Rathke told reporters. "We have not been able to verify them thus far."
There have previously been unconfirmed reports of cooperation between the two countries on ballistic missiles, but nothing specific in the nuclear field.
The U.N. Panel of Experts which monitors compliance with sanctions on North Korea has reported in the past that Pyongyang and Tehran have regularly exchanged ballistic missile technology in violation of U.N. sanctions.
The NCRI said the North Korean delegation was taken secretly to the Imam Khomenei complex, a site east of Tehran controlled by the Defense Ministry. It gave detailed accounts of locations and who the officials met.
It said the delegation dealt with the Center for Research and Design of New Aerospace Technology, a unit of nuclear weaponization research, and a planning center called the Organization of Defensive Innovation and Research, which is under U.S. sanctions.
Reuters could not independently verify the allegations.
"Tehran has shown no interest in giving up its drive to nuclear weapons. The weaponization program is continuing and they have not slowed down the process," NCRI spokesman Shahin Gobadi said.
U.N. watchdog the IAEA, which for years has investigated alleged nuclear arms research by Tehran, declined to comment. North Korean officials were not available for comment.
Several Western officials said they were not aware of a North Korean delegation traveling to Iran recently.
A Western diplomat said there had been proven military cooperation between Iran and North Korea in the past.
North Korean and Iranian officials meet in the course of general diplomacy. On April 23, Kim Yong Nam, North Korea’s ceremonial head of state and Iran's president held a rare meeting on the sidelines of the Asian-African summit in Jakarta.
(Additional reporting by Louis Charbonneau at the United Nations, Parisa Hafezi in Ankara; James Pearson in Seoul and Arshad Mohammed in Washington; editing by Andrew Roche and Christian Plumb)